The field of cranio-maxillofacial (CMF) surgery involves the correction of congenital and acquired deformities of the skull and face. These include dentofacial deformities, congenital deformities, and defects after tumor ablation, post-traumatic defects, and deformities of the temporomandibular joint (TMJ). In the United States each year, a significant number of patients undergo reconstructive surgery for these types of defects and deformities. Due to the complex nature of the craniofacial skeleton, craniofacial reconstructive surgery usually requires extensive pre-surgical planning. Traditional surgical planning methods for this type of the surgery involve a physical examination, plain radiographs (cephalometric radiographs), plaster dental models, three-dimensional (3D) computed tomography (CT) scans, and occasionally CT-based 3D physical models. Unfortunately, these methods are often not adequate for planning complex cranio-maxillofacial deformities. Over the last six years, our Surgical Planning Laboratory has developed a prototype system for computer- aided surgical simulation (CASS). The accuracy of our CASS system has been proven in the Phase I study. The specific aim of the Phase II proposal will be to develop a user-friendly software package that will allow surgeons to plan complex cranio-maxillofacial surgeries from beginning to end. In addition, this newly developed software will be validated following the FDA? rules and regulations. Finally, we will continue to investigate the clinical feasibility of the investigators? CASS. The ultimate goal of this project (Phase III) is to take this product to the market. The field of cranio-maxillofacial (CMF) surgery involves the correction of congenital and acquired deformities of the skull and face. These include dentofacial deformities, congenital deformities, and defects after tumor ablation, post-traumatic defects, and deformities of the temporomandibular joint (TMJ). In the United States each year, a significant number of patients undergo reconstructive surgery for these types of defects and deformities. [unreadable] [unreadable] [unreadable]